 In this lecture, let us discuss cavernous sinus thrombosis. As its name suggests cavernous sinus thrombosis is a serious condition consisting of formation of thrombus in the cavernous sinus or its communicating branches. Structure of head, face and intraoral structures in particular the structures above maxilla. It is the infection of these structures that lead to this condition. Now let's have a brief description about the anatomy of cavernous sinus. Each cavernous sinus is a large venous space situated in the middle cranial fossa on either side of the body of the spinoid bone. A closer look at the sinus shows that the optic chiasma, the internal carotid artery and the optic crack are present superior to the cavernous sinus. The structures in the lateral wall of the cavernous sinus from above downwards are the oculomoto nerve, the cochlear nerve, the ophthalmic and maxillary division of the fifth cranial nerve. All these structures are present in the lateral wall of the cavernous sinus. Structures passing through the center of the cavernous sinus are the internal carotid artery and the sixth cranial nerve which is the abducent nerve. There are a few incoming channels to the cavernous sinus. That means there is blood flow from different regions into the cavernous sinus. From the orbit, the superior of dalmic vein, the inferior of dalmic vein and central vein of retina, drain into the cavernous sinus on either side. The meninges drain into the cavernous sinus via spinopadietal sinus and middle meningeal vein. This is the drainage from meninges to the cavernous sinus. Similarly, drainage from the brain reaches the cavernous sinus through superficial middle cerebral vein and inferior cerebral vein. There are communications between the cavernous sinus and other distanced veins through which their contents get exchanged. For example, the cavernous sinus drains into the transverse sinus through superior petrosal sinus. It also drains into internal jugular vein through the inferior petrosal sinus. This communication is into the internal jugular vein. Also the cavernous sinus drains into the pterygoid plexus of veins through emissary vein that passes through the furamen, ovale and spinosum. Here is the communication from the cavernous sinus into the pterygoid plexus of veins through the emissary vein. The cavernous sinus also flows or drains into the facial vein through superior oftalmic vein. Here is another communication where the cavernous sinus drains into the facial vein via superior oftalmic vein. Also the right and left cavernous sinus communicates through intercavernous sinuses. Here is the intercavernous sinus that forms a communication between the left and right cavernous sinuses. So all these communications are valueless and the blood can flow through them in either direction. The main causative factors of cavernous sinus thrombosis are infections arising from the face, maxillary sinus and maxillary teeth. The less common causes are the infections arising from tonsils, soft palate, middle ear and orbit. Complications of cavernous sinus thrombosis are rapid and occasional death can result due to the infections arising from the upper part of the face. The three possible reasons for these complications are the short distance from the facial regions to the sinuses, frequent and complicated anastomosis of these veins leading to direct communications with the sinuses and also lack of protective valves. Unlike other venous systems of the body, the veins in the facial region are valueless. So all these factors account for the complications arising from cavernous sinus thrombosis. The various bacteria implicated in the sinus thrombosis are streptococci and stephilococci along with some gram-narrative bacteria. Moving on to the clinical features, generalized constitutional symptoms like high-fructuating fever, chills, rapid pulse and sweating are frequently associated with cavernous sinus thrombosis. The initial symptoms present with swelling of the face and edematous involvement of the eyelids. There is pain in the eye and it is also tender to pressure. There is venous obstruction that leads to marked edema and congestion of eyelids. Edema of conjunctiviva due to impaired venous return is also observed. There is pulsating X of thalamus and involvement of the 3rd, 4th, 5th and 6th cranial nerves. So this will result in of thalmoplegia and paracis or paralysis of the lateral rectus muscle of the eye. There is also papillodema with multiple retinal hemorrhage. Epitaxis or nose bleeding is also found due to increased intracranial pressure. These are the initial symptoms associated with cavernous sinus thrombosis. If left untweeted, the late symptoms develop which include thromboflebitis which spread to the other side or there is bilateral signs that can be made out. In advanced stage of cavernous sinus thrombosis, there may be signs of toxemia and meningitis. Positive cavernic sign can also be elicited. What is cavernic sign? It is severe stiffness of the hamstrings. Hamstrings are nothing but posterior thigh muscles. So there are stiff hamstrings which cause an inability to straighten the leg when the hip is flexed to 90 degree. When there is a hip flexion at 90 degree, there is stiffness of the hamstring muscle. It is called positive cavernic sign. What is positive grudinski sign? It is the passive flexion of the neck which causes flexion of both legs and the thighs. As you can see in this diagram as the neck is flexed, there is flexion of the thighs and legs as well. Another positive sign is Biot's respiration. It is an abnormal pattern of breathing characterized by regular deep inspirations followed by a period of apnea. This sign is seen in patients with acute neurological diseases. It is named after the person who characterized the condition. There is also septicemia with leukocytosis and severe acidosis with a positive blood culture. So unless it is treated early, the prognosis of the condition is poor. Eagleton has suggested six criteria for the establishment of diagnosis of cavernous sign is thrombosis. Those six features are a known site of infection, evidence of bloodstream infection, early sign of venous obstruction in the retina, conjunctiva or eyelids, paralysis of the third, fourth and sixth cranial nerves that result from inflammatory edema, abscess formation and involvement of neighboring tissues. There should be an evidence of meningeal irritation. So these are the six criteria suggested by Eagleton in order to establish the diagnosis of cavernous sign is thrombosis. Cavernous sign is thrombosis management includes the use of antibiotics directed at the causative organism and surgery to remove the primary source of infection. Immediate empirical antibiotic overages mandatory which is followed by specific antibiotics which is adjusted to the cultures and sensitivities. Heparinization followed by antibiotic therapy will help prevent extension of thrombosis. Menegitis, ophthalmoplegia, kerinic signs all are confirmatory findings of neurological involvement. Therefore, a neurosurgical consultation is a must. IV manitol helps reduce the brain edema. Likewise, anticoagulants prevent venous thrombosis, surgical drainage and elimination of the primary source of infection is also very important. Hence to conclude cavernous sign is thrombosis is still prevalent though patients now have better survival rates. It needs an early diagnosis and prompt intervention to yield a favorable result. So that's all about the topic. Thank you.